ABSTRACT: Asthma is a
chronic inflammatory disorder of the airways characterized by recurring
episodes of reversible airway obstruction, hyper-responsiveness, wheezing,
breathlessness and coughing. Clinical diagnosis of asthma is based on the
pattern of clinical symptoms and pulmonary fuction tests. Asthma
affectes 5% - 10% of the population and the number of worldwide cases is
approximately 300 milliones. The incidence of this disease is increasing particulry
in western countries [1]. It is the cause of a huge economic burden to national
healthcare services. In a minority of cases, asthma is potentially fatal.
After a period when fatalities appeared to be increasing [2], in recent years
asthma-related mortality has progressively declined due to the develop- ment of
specific asthma disease management programs, as well as the extensive use of in-
haled corticosteroids [3]. Inflammation of the airways is a central component
in asthma. In- flammation is associated with infliltration of the airway wall
with eosinophiles and or neutron- philes mast cell degranulation and T cell active-
tion. Other pathological features include, sub- basement membrane thickening,
loss of epithet- lial cell integrity, goblet cells hyperplasia In- crease in
airway smooth muscle mass. Eosino- phils are thought to be vital in the development
of airway hyperreactivity, with the eosinophil cationic protein playing a
crucial role [4]. The fact that treatment of
asthma with corticos-teroids reduces eosinophils numbers and decreases
airway reactivity further supports this hypothesis.